Upgrade storage servers with latest FreeNAS (11-STABLE)

I arrived at this issue in a circuitous manner...

It started out as trying to fix a race condition that is/was biting a Powder profile. After making some fixes to our latest FreeNAS clientside, I discovered that only one of the six storage servers was running the latest FreeNAS that could use the fixes. So rather than back-porting the fixes, I am upgrading the servers.